For more than sixty years injectable drugs have been packed in glass vials. Such vials typically are formed of glass and have a cylindrical neck terminating in a flanged top or lip, with the opening to the interior of the vial extending through the neck. The neck is sealed by means of a rubber stopper and an aluminum seal or ferrule. The technique used to seal such a vial typically entails moving the vial so that it is compressed between a bottom base and a pressure block or platen. When the vial is compressed in place, a roller or rollers contact the aluminum ferrule below the neck of the vial and force the metal in place permanently, thereby holding the stopper in place and sealing the vial. In short, the usual method for achieving compression of the elastomeric element or stopper is mechanical and dimensionally driven. In particular, the vial is raised a certain distance into the pressure block or platen to apply pressure to the cap assembly. Using this technique, the variations of vial height within the tolerance range of the vial manufacture influence the amount compression achieved, so that some vials may not be adequately capped and sealed.
Accordingly, a need exists for a capping and sealing apparatus which overcomes the drawbacks of the mechanical/dimensional driving of the prior art capping sealing apparatus. The subject invention addresses that need.